Caption: Opium poppy (Papaver somniferum) flowers. Close-up of opium poppies, showing seed head formation at the centre of each flower (green). This poppy is the source of opium, a narcotic resin that contains the alkaloids morphine and codeine. These are used by the pharmaceutical industry as painkillers (analgesics). Opium can be refined to yield the illegal drug heroin. Photographed near Blandford, Dorset, UK.